Sexual mating preferences in vitro and in planta among Japanese isolates of Phytophthora infestans     

Kiyotaka Gotoh  Seishi Akino  Takako Kiyoshi  Shigeo Naito 《Journal of General Plant Pathology》2005,71(1):29-32

The sexual preferences of Japanese isolates of Phytophthora infestans were determined by mating on agar, in broth, or in plants. The influence of their sexual preference was confirmed in the host tissues. Three wild-type isolates and a -glucuronidase (GUS) transformant were co-cultured to identify the origin of antheridia and oogonia. Japanese A1 isolate had a unique sexual preference compared with foreign isolates. It produced self-fertile oospores with about 40% of total gametangia but tended to form antheridia on V-8 agar medium. In addition, oospores were formed in plants, but their sexual preference could not be reflected in vitro.  相似文献   

Role of tumor necrosis factor-alpha and nitric oxide in luteolysis in cattle     

Skarzynski DJ  Jaroszewski JJ  Okuda K 《Domestic animal endocrinology》2005,29(2):340-346

Although prostaglandin (PG) F2alpha is known to be a principal luteolytic factor, its action on the bovine corpus luteum (CL) is mediated by other intra-ovarian factors. Tumor necrosis factor-alpha (TNFalpha) and its specific receptors are present in the bovine CL with the highest expressions at luteolysis. TNFalpha in combination with interferon-gamma reduced progesterone (P4) secretion, increased PGF2alpha and leukotriene C4 (LTC4) production, and induced apoptosis of the luteal cells in vitro. Low concentrations of TNFalpha caused luteolysis, which resulted in a decreased level of P4, and increased levels of PGF2alpha, LTC4 and nitrite/nitrate (stable metabolites of nitric oxide-NO) in the blood. Inhibition of local NO production counteracts spontaneous and PGF2alpha-induced luteolysis. Therefore, NO is a likely candidate for the molecule that mediates PGF2alpha and TNFalpha actions during luteolysis. Both PGF2alpha and TNFalpha increase NO concentrations in blood, and stimulate NO synthase expression on protein level in the bovine CL cells. NO stimulates PGF2alpha and LTC4 secretion, inhibits P4 production and reduces the number of viable luteal cells. TNFalpha and NO induce apoptotic death of the CL by modulating expression of bcl-2 family genes and by stimulating expression and activity of caspase-3. The above findings indicate that TNFalpha and NO play crucial roles in functional and structural luteolysis in cattle.  相似文献   

A novel method for estimating the adaptive ability of guide dogs using salivary sIgA   总被引：1，自引：0，他引：1  

Kikkawa A  Uchida Y  Suwa Y  Taguchi K 《The Journal of veterinary medical science / the Japanese Society of Veterinary Science》2005,67(7):707-712

Salivary secretory immunoglobulin A (sIgA) concentrations of prospective guide dogs for the blind were determined to clarify whether salivary sIgA is useful in evaluating the potential suitability of guide dogs for the blind. Saliva was collected from 73 prospective guide dogs in the kennel on day 1 (the day of separation from volunteer puppy-raisers), 2, 3, 7 and 14 during the estimation period (at about 1 year old). We selected particularly suitable dogs (superior dogs) and unsuitable dogs (inferior dogs) on the basis of the trainers' estimation. All dogs were divided into two groups, those were acceptable dogs would become the guide dogs and rejected dogs could not become guide dogs. The sIgA concentrations in superior dogs gradually increased from day 1 to 14 and those in inferior dogs remained at low levels. Moreover, the sIgA concentrations on day 14 in the acceptable dogs were significantly higher than those in rejected dogs. The cut-off point of sIgA concentrations on day 14 using an ROC curve was 90 EU/ml, and the specificity of the estimation at this point (70.4%) was higher than that of trainers' estimation (50%). Moreover, parallel testing using both trainers' estimation and sIgA estimation, showed that specificity was further improved (79.5%). The present study showed that sIgA concentration was extremely useful in estimating the adaptive ability for guide dogs for the blind.  相似文献   

Aberrant development of mammary glands, but precocious expression of beta-casein in transgenic females ubiquitously expressing whey acidic protein transgene     

Iwamori T  Oosawa M  Nukumi N  Kano K  Sudo K  Naito K  Tojo H 《The Journal of reproduction and development》2005,51(5):579-592

It has been suggested that whey acidic protein (WAP) may function as a protease inhibitor. However, the actual function of WAP remains obscure. We investigated the histological development of the mammary glands of transgenic mice ubiquitously expressing WAP and CAG/WAP transgene. Ubiquitous expression of WAP induced aberrant development of the lobular alveoli of the mammary glands: mammary alveoli that were either aberrantly large or small in size increased in number in the developing mammary glands of these transgenic females during pregnancy and lactation. The expression of beta-casein was precociously induced in the mammary glands of the transgenic females during early pregnancy and accompanying this was a histological observation that abnormally developed lobular alveoli filled with milk proteins appeared in the mammary glands of transgenic females during early pregnancy. However, during lactation, the development of mammary glands was impaired in transgenic females. To investigate the possible paracrine action of WAP associated with mammary gland aberration, we transplanted the mammary tissue of CAG/EGFP transgenic females into the fat pad of virgin CAG/WAP transgenic females and initiated pregnancy by mating. The development of mammary tissue transplanted to the recipient was histologically examined on day 3 of lactation. The results revealed that the development of grafted mammary tissues was impaired in a manner similar to that of the mammary glands of CAG/WAP transgenic females, indicating that the inhibitory effect of WAP acts via a paracrine mechanism. In vitro experiments using HC11 cells with forced expression of exogenous WAP demonstrated the inhibitory function of WAP on proliferation of mammary epithelial cells.  相似文献   

Chicken peripheral blood CD3+CD4-CD8- cells are regulated by endocrine and nerve systems     

Kushima K  Yoshida K  Fujita M  Shigeta A  Horiuchi H  Matsuda H  Furusawa S 《The Journal of veterinary medical science / the Japanese Society of Veterinary Science》2004,66(2):143-148

The existence of CD3(+)CD4(-)CD8(-) T cells in thymus and spleen has already been known. However, because of the presence of large amounts of thrombocytes in peripheral blood (PB), the proportion of CD3(+)CD4(-)CD8(-) T cells in PB has yet to be investigated. Therefore, the proportion of peripheral T cell-subsets was investigated in 6-week-old chickens. The percentage of CD3(+) cells, CD4(+) cells, CD8 alpha(+) cells, CD8 beta(+), and CD3(+)CD4(-)CD8(-) cells was 76%, 41%, 14%, 5%, and 15%, respectively. The proportion of CD3(+)CD4(-)CD8(-) cells in PB increased during egg-laying periods and in chickens treated with an analog of estrogen, while it decreased with age and in response to restraint stress. All of the CD3(+)CD4(-)CD8(-) cells expressed TCR1, and did not have NK activity. CD3(+)CD4(-)CD8(-) cells represent about 60% of peripheral TCR1(+) cells. These findings indicate that the proportion of CD3(+)CD4(-)CD8(-) cells is regulated by the endocrine and nerve systems.  相似文献   

Identification of osmotic stress-responsive genes from Leymus mollis,a wild relative of wheat (Triticum aestivum L.)     

Mohamed Elsadig Eltayeb Habora  Amin Elsadig Eltayeb  Hisashi Tsujimoto  Kiyoshi Tanaka 《Breeding Science》2012,62(1):78-86

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Effects of cortisol on pregnancy rate and corpus luteum function in heifers: an in vivo study     

Duong HT  Piotrowska-Tomala KK  Acosta TJ  Bah MM  Sinderewicz E  Majewska M  Jankowska K  Okuda K  Skarzynski DJ 《The Journal of reproduction and development》2012,58(2):223-230

To determine whether glucocorticoids affect the function of the bovine corpus luteum (CL) during the estrous cycle and early pregnancy, we examined the effects of exogenous cortisol or reduced endogenous cortisol on the secretion of progesterone (P4) and on pregnancy rate. In preliminary experiments, doses of cortisol and metyrapone (an inhibitor of cortisol synthesis) were established (n=33). Cortisol in effective doses of 10 mg blocked tumor necrosis factor-induced prostaglandin F(2α) secretion as measured by its metabolite (PGFM) concentrations in the blood. Metyrapone in effective doses of 500 mg increased the P4 concentration. Thus, both reagents were then intravaginally applied in the chosen doses daily from Day 15 to 18 after estrus (Day 0) in noninseminated heifers (n=18) or after artificial insemination (n=36). Pregnancy was confirmed by transrectal ultrasonography between Days 28-30 after insemination. Plasma concentrations of P4 were lower in cortisol-treated heifers than in control heifers on Days 17 and 18 of the estrous cycle (P<0.05). However, the interestrus intervals were not different between control and cortisol-treated animals (P>0.05). Moreover, metyrapone increased P4 and prolonged the CL lifespan in comparison to control animals (P<0.05). Interestingly, in inseminated heifers, cortisol increased the pregnancy rate (75%) compared with control animals (58%), whereas metyrapone reduced the pregnancy rate to 16.7% (P<0.05). The overall results suggest that cortisol, depending on the physiological status of heifers (pregnant vs. nonpregnant), modulates CL function by influencing P4 secretion. Cortisol may have a positive influence on CL function during early pregnancy, leading to support of embryo implantation and resulting in higher rates of pregnancy in heifers.  相似文献   

Normal calves produced after transfer of embryos cultured in a chemically defined medium supplemented with epidermal growth factor and insulin-like growth factor I following ovum pick up and in vitro fertilization in Japanese black cows     

Sakagami N  Umeki H  Nishino O  Uchiyama H  Ichikawa K  Takeshita K  Kaneko E  Akiyama K  Kobayashi S  Tamada H 《The Journal of reproduction and development》2012,58(1):140-146

The objective of this study was to examine whether high concentrations of epidermal growth factor (EGF) and/or insulin-like growth factor I (IGF-I) would have a beneficial effect on bovine embryo development in vitro and to obtain normal calves by using an ovum pick up method and embryo culture in a chemically defined medium. When compared with controls, EGF (100 or 200 ng/ml) or IGF-I (50 or 100 ng/ml) significantly increased the rate of embryos that developed into blastocysts during an 8-day culture after the in vitro fertilization of oocytes obtained from ovaries from a slaughterhouse. IGF-I induced a dose-dependent increase in cell number in both the inner cell mass and the trophectoderm, whereas EGF stimulated proliferation only in the inner cell mass. A combination of EGF (100 ng/ml) and IGF-I (50 ng/ml) produced an additive effect, and embryos developed into blastocysts at a comparatively high rate (27.9%) compared with controls (12.0%). A similar rate of development was achieved using a combination of EGF and IGF-I in the culture of embryos following ovum pick up by ultrasound-guided transvaginal follicular aspiration and in vitro fertilization, and 5 blastocysts that developed after the culture were transferred into uteri; two embryos implanted, and normal calves were born. These results suggest that the combined use of EGF and IGF-I makes bovine embryo culture in a chemically defined medium a practical and useful procedure for producing blastocysts, and its application to embryo culture following ovum pick up and in vitro fertilization could be useful for producing normal calves.  相似文献   

An effective approach to sustainable small-scale irrigation developments in Sub-Saharan Africa     

Michihiko Sakaki  Kiyoshi Koga 《Paddy and Water Environment》2013,11(1-4):1-14

Countries in Sub-Saharan Africa (SSA) that depend on foreign aid once political independence is gained, continue to be affected by changing aid modalities led by aid communities. It has been claimed that previous irrigation programs in SSA have not improved agricultural production as expected, and that the budget for implementation of further irrigation development has then been decreased. As a result, small-scale operations, which are part of participatory integrated rural development (PIRD), have become mainstream in the implementation of irrigation development in SSA. A small-scale irrigation development (SSID) was considered capable of attracting initial investment, required shorter construction periods, was comparatively easy to design, farmers were able to maintain the system themselves, and it had a lesser environmental impact. In general, to achieve a sustainable irrigation scheme, three systems must be established: a “water utilization system”; an “operation and maintenance (O&M) system”; and a “succession system”. This paper discusses SSID in SSA with regard to a number of important factors, i.e., environmental, economic, and social factors, all of which impact on the sustainability of SSID. The progress of low-input, effective, and sustainable irrigation development (LESID) and the impact of changing aid modalities is followed in three countries, Ghana, Malawi, and Tanzania. In addition, the future effective implementation of SSID by way of LESID in other SSA countries is discussed. A self-supported SSID (as employed in Malawi) is currently considered the most appropriate LESID for least developed countries (LDCs) in SSA.  相似文献   

Induction of the Expressions of Antioxidant Enzymes by Luteinizing Hormone in the Bovine Corpus Luteum     

Syota KAWAGUCHI  Ryosuke SAKUMOTO  Kiyoshi OKUDA 《The Journal of reproduction and development》2013,59(3):219-224

Luteoprotective mechanisms of luteinizing hormone (LH) involved in the maintenance of bovine corpus luteum (CL) function have not been completely clarified. Since antioxidant enzymes are well documented as antiapoptotic factors in the CL of many mammals, we hypothesized that the luteoprotective action of LH is mediated by stimulating the local production and action of antioxidant enzymes. To test the above hypothesis, in the present study, we examined the mechanisms involved in the luteoprotective actions of LH. Cultured bovine luteal cells obtained from the CL at the mid-luteal stage (days 8–12 of the estrous cycle) were treated with LH (10 ng/ml), onapristone (OP; a specific progesterone receptor antagonist, 100 μM) and diethyldithiocarbamate [DETC; an inhibitor of superoxide dismutase (SOD), 100 μM] for 24 h. LH in combination with or without OP significantly increased the mRNA and protein expressions of manganese SOD (Mn-SOD) and catalase (CATA) and SOD activity. While LH alone significantly increased the mRNA and protein expressions of SOD containing copper and zinc (Cu,Zn-SOD), OP in combination with or without LH significantly decreased the mRNA and protein expressions of Cu,Zn-SOD. In addition, Cu,Zn-SOD, Mn-SOD and CATA mRNA expressions were higher at the mid luteal phase than the other luteal phases. LH in combination with DETC significantly decreased LH-increased cell viability. The overall results suggest that LH increases cell viability by LH-increased antioxidant enzymes, resulting in maintenance of CL function during the luteal phase in cattle.  相似文献